Throttle Position Sensor: Testing and Inspection

A Tech 1 scan tool displays throttle position in volts. Voltage should increase at a steady rate as throttle is moved toward wide open throttle. The PCM has the ability to auto-zero the Throttle Position (TP) sensor voltage if it is between 0.29 volt (290 mV) and 0.98 volt (980 mV). This means that any voltage between 0.29 and 0.98 volt will be determined by the PCM to be 0% throttle. Tech 1 scan tools have the ability to read the throttle angle and should display 0% when the throttle is closed, A failure in the TP sensor or circuit should set a DTC 21 or 22.